These powerful images capture the spear-wielding tribes of Papua new Guinea who believe they are possessed with the spirit of the crocodile. They show how the Kangunaman clansmen scar their backs to resemble reptile scales while the Huli Wigmen wear elaborate headdresses to signal they are ready for battle. (Photo by Trevor Cole/Media Drum World)

These photographs of hundreds of ducks following their leader down a river are truly mesmerizing. Rafeur Rahman of Bangladesh climbed a high bridge and saw hundreds of ducks apparently playing a game of follow the leader. More than 500 ducks live on the river, where the mosses and snails provide the perfect habitat. Here: Ducks in the river Baral in Bangladesh. (Photo by Rafeur Rahman/Caters News Agency)

Andrey Karr from Western Riders Slacklines at sunset above big waves in Nazare, Portugal on December 27, 2017. (Photo by Aidan Williams/National Geographic Travel Photographer of the Year Contest)

Czech model Petra Nemcova attends Fashion For Relief during the 71st annual Cannes Film Festival at Hangar 16 Airport of Cannes Mandelieu in Cannes, France, 13 May 2018. (Photo by Arnold Jerocki/EPA/EFE)

American model Bella Hadid has wardrobe malfunction as she runs with leftovers from lunch with friends at Bar Pitti in New York, United States of America on June 2, 2018. (Photo by Peter Parker/Splash News and Pictures)

A rickshaw puller transports passengers through a water-logged street after heavy rain in Kolkata, India on June 26, 2018. (Photo by Rupak De Chowdhuri/Reuters)

Australian rapper Amethyst Amelia Kelly, known professionally as Iggy Azalea is seen on the set of Extra TV on July 10, 2018 in Los Angeles, California. (Photo by Splash News and Pictures)

In the mountains of central Vietnam, a colossal pair of hands lifts a golden thread of walkway high above the clifftops, as if the mountain itself has sprouted limbs. Here: A giant hand structure at the Gold Bridge is seen on Ba Na hill near Danang city, Vietnam on August 1, 2018. (Photo by Reuters/Kham)